Apparatus for reading sound on cinematograph sound films



May 8, 1934. A. G. JOANNIDES 1,957,539

APPARATUS FOR READING SOUND ON CINEMATOGRAPH SOUND FILMS Filed May 193s fm/eniar Alexandre e01yes fiannzid'ea 1% ATTORNEYS Patented May 8, 1934 SPAE'ENT @FFECE APPARATUS FOR READING SOUND N CENEMATOGEAPH SOUND FELMS Aiexandre Georges .l'oannides, Paris, France, as-

signor to Societe Pour LExpieitation Des Ere-vets, A. G. 1., Paris, France Application May 19, 1933, Serial No. 671,795 in France September 15, 1932 4 Claims.

This invention relates to apparatus for reading sound on cinematograph sound films of the kind including a reducing optical system co-operating with an aperture through which a pencil 5 of light rays is projected onto the sound track.

The chief object of the invention is to provide new or improved means for adjusting the pos tion of the pencil of light rays on the sound track by varying the position of the effective part of the aperture, i. e. that part of the aperture which is utilized for the passage of the light rays. In devices already known for displacing the utilized part of the aperture, it has already been proposed to employ a slide having a longitudinal bore of a length corresponding to the length of the aperture utilized, which slide was displaced in a direction parallel to the aperture, the aperture being thus uncovered at the desired point by the displacement of the slide so as to vary the position of the light rays on the sound track.

Apparatus for reading sound on cinematograph sound films according to the invention includes a rotatable cap or member having an opening adapted to co-operate with the aperture, said opening being so constructed and arranged that upon the cap or member being rotated the position or" the effective part of the aperture will be varied whilst maintaining the length of the effective part of the aperture substantially uniform. The cap which is preferably of a tubular construction, is rotatably mounted upon the casing of the reducing optical system, the opening being situated at the upper end of the cap and of any suitable form which will fulfil the object of the invention. For example, the opening, eccentrically arranged, may be formed by two symmetrical spiral portions or by two cycloidal portions, or practically simply by the osculating circumference of these curves.

Referring to the drawing:

Figure 1 is a perspective view of a reducing optical system for use in reading sound on cinematograph sound films showing the invention applied thereto.

Figure 2 is a perspective view showing the various component parts separated.

Figure 3 is a plan view to an enlarged scale.

In the construction illustrated the reducing optical system includes a tubular casing l which is adapted to be mounted within a bracket or other supporting member in any suitable manner, the casing carrying at its lower end a suitable combination of reducing lenses disposed within a lens mounting 2 screwing into the lower end of the casing, the casing being split longitudinally (Q1. HEM-109.3)

at one or more points to ensure its screw-threads gripping firmly the corresponding screw-threads on the lens mounting. The upper end of the casing carries two part-circular plates 3 screwed or otherwise secured in position and spaced apart slightly to constitute a slot-like aperture 4 through which a pencil of light rays is directed on its way to the sound track. The adjacent edges of the plates are preferably undercut or bevelled as at 5. The upper end of the casing carries a cap or member 6, the depending skirt 7 of which is milled upon its exterior to enable it to be readily rotated when desired, the cap containing a bi-convex lens 8 situated at its upper end, the cap being cut away to provide a hole or opening 9 which is arranged eccentrically. The effective length of the aperture 4 exposed by the cap is governed by the circular hole or opening 9, the action of rotating the cap about the axis of the tubular casing causing the position of the eifec tive part of the aperture to be altered, the length of the eifective part of the aperture being maintained substantially constant. In order to render the effective length of the aperture still further uniform, the upper end of the tubular casing is turned over the lens 8 as at 10, (see particularly Figure 3), the edge of the hole or opening 9 extending beneath the part 10 at one point, as shown in Figure 3, that part of the opening 9 utilized for the passage of the light rays being bordered by the greater part of the edge of the opening 9 and that part of the edge of the portion 10 overlapping the opening.

The skirt of the cap 6 is split at one or more points as at 11 and thereby grips the walls of the casing 1 frictionally, the edges of the skirt adjacent the split portions being bent inwardly at 12 to enter a circumferential groove 13 in the walls of the tubular casing, and thereby maintain the cap in position upon the casing.

What I claim and desire to secure by Letters Patent of the United States is:-

1. Apparatus for reproducing sound from film having a sound track, comprising a tubular casing, a system of reducing lenses disposed in said casing, said casing being formed to constitute an aperture for directing through the same a pencil of light rays on to the sound track, a cap rotatably mounted upon said casing, and means for varying the position of the effective part of said aperture in line with its longitudinal dimension upon rotation of said cap whilst maintaining the length of the effective part of said aperture substantially uniform, comprising an eccentrically arranged window cooperating with said 1104 aperture and formed by a cut-away portion of said cap.

2. Apparatus for reproducing sound from film having a sound track, comprising a tubular casing, a system of reducing lenses disposed in said casing, said casing being formed to constitute an aperture for directing through the same a pencil of light rays on to the sound track, a cap rotatably mounted upon said casing, and means for varying the position of the effective part of said aperture in line with its longitudinal dimension upon rotation of said cap whilst maintaining the length of the effective part of said aperture substantially uniform, comprising an eccentrically arranged substantially circular window 00- operating with said aperture and formed by a cut-away portion of said cap.

3. Apparatus for reproducing sound from film having a sound track, comprising a tubular casing, a system of reducing lenses disposed in said casing, which casing at its upper end carries two plates mounted in spaced relationship and which together constitute a diametrically arranged aperture for directing through the same apencil of light rays on to the sound track, a cap rotatably mounted upon said casing, and means for varying the position of the effective portion of said aperture in line with its longitudinal dimension upon rotation of said cap whilst maintaining the length of said effective portion of said aperture substantially uniform, comprising an eccentrically arranged window cooperating with said aperture and formed by a cut-away portion of said cap.

4. Apparatus for reproducing sound from film having a sound track, comprising a tubular casing, a system of reducing lenses disposed in said casing, which casing at its upper end carries two plates mounted substantially in the same plane in spaced relationship so as to constitute together a diametrically arranged and uniform aperture for directing through the same a flat pencil of light rays on to the sound track, a cap superposed upon said plates and rotatably mounted upon said casing, and means for varying the position of the effective portion of said aperture along its length upon rotation of said cap uponthe casing while maintaining the length of said effective portion of said aperture practically uniform, comprising an eccentrically arranged circular window cooperating with said aperture so as to cover portions of either or both ends of the latter, which window is formed by a cut-away portion in the top of said cap.

A. G. JOANNIDES. 

